docs: def restart(gandi, resource, background, force):
      """Restart a PaaS instance.
  
      Resource can be a vhost, a hostname, or an ID
      """
      output_keys = ['id', 'type', 'step']
  
      possible_resources = gandi.paas.resource_list()
      for item in resource:
          if item not in possible_resources:
              gandi.echo('Sorry PaaS instance %s does not exist' % item)
              gandi.echo('Please use one of the following: %s' %
                         possible_resources)
              return
  
      if not force:
          instance_info = "'%s'" % ', '.join(resource)
          proceed = click.confirm("Are you sure to restart PaaS instance %s?" %
                                  instance_info)
  
          if not proceed:
              return
  
      opers = gandi.paas.restart(resource, background)
      if background:
          for oper in opers:
              output_generic(gandi, oper, output_keys)
  
      return opers